I know you can make it, but cant remember how to put heart cake together without the shaped pan??

I'd use a templet and cut a sheet cake into the shape wanted. I'd recommend freezing the sheet cake first, making it easier to carve. Should give you a fine heart.

it should be one square pan, and one circle pan

Cut the circle in half, turn the square to a diamond shape and put each half circle on each side, there you have a heart

Hope that helps!

I need a 12 inch heart for this weekend and only have a 9 inch. I made a 12 inch round cake and will make a template to make a 12 inch heart.
I'm sure it will work!

I've done it just carving a large round cake. To get a good shape, fold a piece of parchment in half, and draw half a heart with the centre along the crease. Make sure the rounded part on the top and point at the bottom fits onto your cake, ensuring the middle crease is right in the centre of the cake (like from 12 to 6 o'clock). Cut the outline and open the paper and you have your evenly-shaped heart. Check the fit on your cake and adjust as necessary before carving. And avoid carving a very freshly baked cake...day-old, or refrigerated is best. Good luck!

This sounds more complicated than it really is, trust me!

The easiest thing to do is as asschergirl said. Bake one 8" square and one 8" round. Cut the round in half and attach each half to adjoining sides of the square.

I agree with the square and circle method... but carving= cake balls! LOL